吉林延边和龙地区满河组安山岩岩石成因及构造背景研究

Petrogenesis and tectonic setting of andesite of Manhe Formation in Helong area of Yanbian,Jilin Province

对吉林省延边和龙地区满河组安山岩进行了地球化学研究。满河组安山岩SiO 2质量分数为65.03%~66.25%,K 2O质量分数为1.18%~3.135%,属于中钾钙碱性-高钾钙碱性系列,富集轻稀土元素(LREE)和大离子亲石元素(LILE,Rb、U、K),亏损重稀土元素和高场强元素(HREE)(HFSE,Nb、Ta、P、Ti),与活动大陆边缘火山岩特征相似,其原始岩浆来源于下地壳的部分熔融。结合前人的区域地质调查资料,认为满河组安山岩形成于活动大陆边缘构造背景下,与古亚洲洋板块向南俯冲于华北板块之下有关。

The authors deal with the geochemistry of andesite of Manhe Formation in Helong area of Yanbian,Jilin Province.In andesite of Manhe Formation,the mass fraction of SiO 2 is 65.03%~66.25%,that of K 2O was 1.18%~3.135%.It belongs to medium potassium calcium alkaline-high potassium calcium alkaline series,which enriched in LREE and LILE,Rb,U,K,and depleted in HREE and HFSE,Nb,Ta,P,Ti.It is similar to the volcanic rocks in the active continental margin,the original magma originated from partial melting of the lower crust.Based on the previous regional geological survey data,the authors believe that the andesite of the Manhe Formation was formed under the active continental margin tectonic background,which is related to the southward subduction of the paleo Asian Ocean plate under the North China plate.